1. Field of the Invention
The invention relates to a method for carrying out a dynamic range compression in traffic photography for representation having greater detail fidelity in images created in association with traffic monitoring installations.
2. Description of the Background Art
In traffic photography, for the most part images are created in which the driver in the vehicle cabin appears very dark, whereas the license plate appears strongly over-illuminated owing to its retroreflective property. A dynamic range compression can often be successfully applied in order to brighten up the dark regions in images with a high dynamic range, and to improve the visibility of low contrast details in said regions without destroying the information in the brighter regions. In this case, a copy of the image is converted into a contrast mask over which the image is superposed. In the process, brightness and contrast must be manually matched for each image so that the images thus corrected do not appear unnatural, or even like a photomontage.
When the images from the traffic monitoring installations come to be evaluated in the evaluation offices (backoffices) of the authorities or commissioned organizations, there is a need for daily manual matching of several thousand images, something which entails a considerable extra outlay in time, but also an additional burden on the staff. In extreme cases, fines can be time barred when a blockage results in the processing of the images. Furthermore, the manual matching is open to the subjective influences of the respective person who is processing the image.